1. Field of the Invention
The present invention relates to a method for transferring a liquid fluid, particularly liquid metal, such as magnesium, and a transfer system for carrying out said method.
2. Description of the Prior Art
A known method in transferring molten magnesium from a supply vessel to a receiving container comprises using a centrifugal pressure pump mounted near the bottom in the supply vessel to force the metal through a pipe conduit into the receiving container.
As the centrifugal pump must be arranged stationary at the bottom of the supply vessel because the metal level in the vessel is sinking as the metal melt is removed, it is necessary that the pump rotor shaft be quite a long one, e.g. two meters, and, therefore, the lower bearing(s) supporting the shaft have to be located below the molten metal level. These bearings are mounted on a support frame normally comprising a plurality of support struts dimensioned to the length of the shaft and the maximum metal melt level in the vessel. The temperature of the melt is over 700.degree. C. During the operation the bearings and the support struts are subjected to a combination of thermic and dynamic stresses with the consequence that the struts become gradually soft and the shaft bends out of line. The result is that the bearings wear relatively quickly and a pump of the kind stated has normally an operation time of about a week before it has to be dismantled for overhaul.